# PostgreSQL 18 → 19 Beta 3 GUC diff

> Core configuration parameters added, removed, or changed in boot default between PostgreSQL 18 and 19 Beta 3.
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> [!NOTE]
> **Fact.** The measured inventory changes from 399 to 419 settings: 22 added, 6 boot-default changes, and 2 removed.

## Added parameters {#added}

| Parameter | Type | Context | Boot default | Category |
| --- | --- | --- | --- | --- |
| [`autovacuum_analyze_score_weight`](/parameters/autovacuum-analyze-score-weight/) | `real` | `sighup` | `1` | Vacuuming / Automatic Vacuuming |
| [`autovacuum_freeze_score_weight`](/parameters/autovacuum-freeze-score-weight/) | `real` | `sighup` | `1` | Vacuuming / Automatic Vacuuming |
| [`autovacuum_max_parallel_workers`](/parameters/autovacuum-max-parallel-workers/) | `integer` | `sighup` | `0` | Vacuuming / Automatic Vacuuming |
| [`autovacuum_multixact_freeze_score_weight`](/parameters/autovacuum-multixact-freeze-score-weight/) | `real` | `sighup` | `1` | Vacuuming / Automatic Vacuuming |
| [`autovacuum_vacuum_insert_score_weight`](/parameters/autovacuum-vacuum-insert-score-weight/) | `real` | `sighup` | `1` | Vacuuming / Automatic Vacuuming |
| [`autovacuum_vacuum_score_weight`](/parameters/autovacuum-vacuum-score-weight/) | `real` | `sighup` | `1` | Vacuuming / Automatic Vacuuming |
| [`debug_exec_backend`](/parameters/debug-exec-backend/) | `bool` | `internal` | `off` | Preset Options |
| [`debug_print_raw_parse`](/parameters/debug-print-raw-parse/) | `bool` | `user` | `off` | Reporting and Logging / What to Log |
| [`effective_wal_level`](/parameters/effective-wal-level/) | `enum` | `internal` | `replica` | Preset Options |
| [`enable_eager_aggregate`](/parameters/enable-eager-aggregate/) | `bool` | `user` | `on` | Query Tuning / Planner Method Configuration |
| [`hosts_file`](/parameters/hosts-file/) | `string` | `postmaster` | — (not set) | File Locations |
| [`io_max_workers`](/parameters/io-max-workers/) | `integer` | `sighup` | `8` | Resource Usage / I/O |
| [`io_min_workers`](/parameters/io-min-workers/) | `integer` | `sighup` | `2` | Resource Usage / I/O |
| [`io_worker_idle_timeout`](/parameters/io-worker-idle-timeout/) | `integer` | `sighup` | `60000 ms` (1 min) | Resource Usage / I/O |
| [`io_worker_launch_interval`](/parameters/io-worker-launch-interval/) | `integer` | `sighup` | `100 ms` | Resource Usage / I/O |
| [`log_autoanalyze_min_duration`](/parameters/log-autoanalyze-min-duration/) | `integer` | `sighup` | `600000 ms` (10 min) | Reporting and Logging / What to Log |
| [`max_repack_replication_slots`](/parameters/max-repack-replication-slots/) | `integer` | `postmaster` | `5` | Replication / Sending Servers |
| [`min_eager_agg_group_size`](/parameters/min-eager-agg-group-size/) | `real` | `user` | `8` | Query Tuning / Planner Cost Constants |
| [`password_expiration_warning_threshold`](/parameters/password-expiration-warning-threshold/) | `integer` | `sighup` | `604800 s` (7 d) | Connections and Authentication / Authentication |
| [`ssl_sni`](/parameters/ssl-sni/) | `bool` | `sighup` | `off` | Connections and Authentication / SSL |
| [`timing_clock_source`](/parameters/timing-clock-source/) | `enum` | `superuser` | `auto` | Resource Usage / Time |
| [`wal_sender_shutdown_timeout`](/parameters/wal-sender-shutdown-timeout/) | `integer` | `user` | `-1 ms` | Replication / Sending Servers |
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## Boot-default changes {#default-changes}

| Parameter | PG18 | PG19 Beta 3 | Category |
| --- | --- | --- | --- |
| [`default_toast_compression`](/parameters/default-toast-compression/) | `pglz` | `lz4` | Client Connection Defaults / Statement Behavior |
| [`jit`](/parameters/jit/) | `on` | `off` | Query Tuning / Other Planner Options |
| [`log_lock_waits`](/parameters/log-lock-waits/) | `off` | `on` | Reporting and Logging / What to Log |
| [`max_locks_per_transaction`](/parameters/max-locks-per-transaction/) | `64` | `128` | Lock Management |
| [`server_version`](/parameters/server-version/) | `18.6 (Debian 18.6-1.pgdg13+2)` | `19beta3 (Debian 19~beta3-1.pgdg13+1)` | Preset Options |
| [`server_version_num`](/parameters/server-version-num/) | `180006` | `190000` | Preset Options |
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## Removed parameters {#removed}

| Parameter | Last type | Context | Last boot default | Category |
| --- | --- | --- | --- | --- |
| [`escape_string_warning`](/parameters/escape-string-warning/) | `bool` | `user` | `on` | Version and Platform Compatibility / Previous PostgreSQL Versions |
| [`io_workers`](/parameters/io-workers/) | `integer` | `sighup` | `3` | Resource Usage / I/O |
{.full-width}

## Method {#method}

The three lists compare the pinned PG18 and PG19 Beta 3 `pg_settings` snapshots directly. A default change is a change in the `boot_val` plus `unit` pair; `setting` is excluded so an `initdb`-generated value is not mistaken for the compiled boot default.

- [Machine-readable diff data](/data/diffs.json)
- [Complete GUC JSONL](/data/guc.jsonl)